A typical circuit board system comprises a circuit board furnished with electrical components. The circuit board comprises a body made of one or more layers of electrically insulating material and electrical conductors on one or both of the surfaces of the circuit board and/or between the layers of the electrically insulating material. Each of the electrical components can be, for example, an integrated circuit such as a processor or a memory, or a discrete component such as a resistor, a capacitor, an inductor, a transistor, or a diode. Furthermore, the circuit board system may comprise also other elements than electrical components. Examples of the other elements are heat sinks and mechanical support arms. Commonly used means for attaching elements such as heat sinks and mechanical support arms are spring-fasteners because they are relatively cost-effective and easy to assemble and disassemble.
Publication US20090154109 describes a circuit board system comprising a heat sink thermally contacted with an electronic component and a spring-fastener securing the heat sink to a circuit board. The spring-fastener comprises a pressing portion disposed on the heat sink and a pair of resilient latching portions extending from opposite ends of the pressing portion. Each latching portion comprises a hook for engaging with a corresponding securing member mounted on the circuit board.
A circuit board system can be subjected to unintentional mechanical impacts in many situations, and there have been cases where a spring-fastener of the kind described above has been unintentionally opened when handling a circuit board system. Therefore, there is a need for secure spring-fasteners so as to minimize the risk of unintentional opening.